net: ravb: Fix error handling in ravb_probe

net: ravb: Fix error handling in ravb_probe

In ravb_probe(), we were missing a couple of things in the error
handling path:

  * We must unregister the MDIO bus before freeing the corresponding
    struct mii_dev instance to avoid the potential for use-after-free
    bugs.

  * We must free the resources acquired by clk_get_bulk() even if the
    clocks have not yet been enabled.

Fixes: 8ae51b6f324e ("net: ravb: Add Renesas Ethernet RAVB driver")
Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>